Draft Report 

For the Weldon Spring Site Work Group 

SC&A’S EVALUATION OF NIOSH’S RESPONSE OF 

SEPTEMBER 7, 2011, TO DAILY WEIGHTED EXPOSURE 

BLUNDERS IN WELDON SPRING DATA

Prepared by 

John Stiver 

Ron Buchanan 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

Saliant, Inc. 

5579 Catholic Church Road 

Jefferson, Maryland 21755

September 2011 

Disclaimer 

This document is made available in accordance with the unanimous desire of the Advisory Board on 

Radiation and Worker Health (ABRWH) to maintain all possible openness in its deliberations. However, 

the ABRWH and its contractor, SC&A, caution the reader that at the time of its release, this report is predecisional and has not been reviewed by the Board for factual accuracy or applicability within the 

requirements of 42 CFR 82. This implies that once reviewed by the ABRWH, the Board’s position may 

differ from the report’s conclusions. Thus, the reader should be cautioned that this report is for 

information only and that premature interpretations regarding its conclusions are unwarranted.
Effective Date: 

September 27, 2011 

Revision No. 

0 –Draft 

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Evaluation of NIOSH Response to DWE Blunders 

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NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82.

Document No.: Evaluation of NIOSH 

Response to DWE Blunders 

Effective Date: 

 Draft – September 27, 2011 

S. COHEN & ASSOCIATES: 

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

NIOSH Dose Reconstruction Program Revision No. 

0 (Draft) 

SC&A’s Evaluation of NIOSH’s Response of 

September 7, 2011, to Daily Weighted Exposure 

Blunders in Weldon Spring Data 

Page 2 of 4 

Task Manager: 

___________________________ Date:___________ 

Ron Buchanan 

Supersedes: 

N/A 

Project Manager: 

___________________________ Date:___________ 

John Mauro, PhD, CHP 

Peer Reviewer(s): 

 Joseph Fitzgerald 

 John Mauro 

 

Record of Revisions 

Revision 

Number 

Effective 

Date Description of Revision 

0 (Draft) 09/27/2011 Initial issue 
Effective Date: 

September 27, 2011 

Revision No. 

0 –Draft 

Document No. 

Evaluation of NIOSH Response to DWE Blunders 

Page No. 

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SC&A Response to DWE Blunder Issue 3 SC&A – September 2011 

NOTICE: This information is protected by Privacy Act 5 U.S.C. § 552a; disclosure to any third party without the 

written consent of the individual to whom the information pertains is strictly prohibited. 

1 INTRODUCTION 

NIOSH’s Response of September 7, 2011 

The National Institute for Occupational Safety and Health (NIOSH) provided a response 

(NIOSH 2011) to the Weldon Spring Site (WSS) Special Exposure Cohort (SEC) issue (SC&A 

2010) concerning “blunders”1

 in the original daily weighted exposure (DWE) air concentration 

data as discussed at the WSS Work Group meeting of May 9, 2011. 

The following presents SC&A’s evaluation of NIOSH’s September 7, 2011, response. 

2 SC&A’S EVALUATION OF NIOSH’S SEPTEMBER 7, 2011, RESPONSE TO 

WSS ISSUE #1b, BLUNDERS IN DWE DATA 

SC&A evaluated NIOSH’s response to the issue of blunders in the DWE original data and found 

the following. 

1. Limited data – NIOSH’s white paper acknowledges that the available raw data are a 

“small” proportion of the total DWE data set that will be used in dose reconstruction 

(DR), but does not quantify that proportion (i.e., what percentile). The DWE data sets to 

be used in DR are identified in Tables 6-4 (uranium) and 6-5 (thorium) of the SEC-00143 

petition evaluation report (NIOSH 2010). 

2. Representativeness of the limited data – NIOSH’s report does not indicate the extent to 

which the available raw data are representative of the DWE data identified in NIOSH 

(2010). It is not clear from the report if the evaluated data pertains to the highest DWEs 

for each building, year and job category. For example, MCW 1961 (SRDB 14945) 

contains 27 pages of raw data calculations that are applicable to the metals plant (301) in 

the years 1958–1959. However, Table 6-4 (uranium) of NIOSH 2010 contains no DWEs 

for Building 301 in 1958, and only one value for one operation in 1959; that value is the 

second lowest DWE for Building 301 for all 7 years reported. 

3. Type and Magnitude of Error – The types and relative magnitudes of the errors 

identified in NIOSH’s white paper are similar to those found in Davis and Strom (2008). 

That is, the average blunder resulted in about a factor of 2 underestimate, while the 

largest blunders resulted in an order of magnitude underestimate. 

4. Application of Findings – NIOSH’s white paper presents preliminary findings only. It 

does not propose a method for incorporating this information into the overall uncertainty 

in DWEs for which raw data are not available. At the WSS Work Group meeting held on 

September 13, 2011, DCAS indicated that they believe the GSD of 5 based on the Davis 

and Strom report adequately bounds any additional uncertainties due to blunders. 

 1 The ISO definition emphasizes that a blunder is often considered a serious mistake caused by ignorance 

or confusion; stupidity, which is included in some U.S. English definitions of blunder, is not implied in this case 

(ISO 1995).
Effective Date: 

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Revision No. 

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Evaluation of NIOSH Response to DWE Blunders 

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SC&A Response to DWE Blunder Issue 4 SC&A – September 2011 

NOTICE: This information is protected by Privacy Act 5 U.S.C. § 552a; disclosure to any third party without the 

written consent of the individual to whom the information pertains is strictly prohibited. 

However, SC&A believes that it is incumbent on DCAS to provide quantitative evidence 

supporting their position. 

3 SUMMARY 

SC&A believes that NIOSH should address the representativeness of the limited available raw 

data to the data sets to be used in DR and propose a method for incorporating uncertainties due to 

blunders into the overall uncertainty in DWEs for which raw data are not available. Because 

NIOSH’s use of DWEs to estimate inhalation intakes extends beyond WSS, the method should 

be generalized and applicable to all affected sites. 

4 REFERENCES 

Davis, A.J., and D.J. Strom, 2008. Uncertainty and Variability in Historical Time-Weighted 

Average Exposure Data, Health Physics, Vol. 94. February 2008. SRDB 41616. 

ISO 1995. Guide to the expression of uncertainty in measurement. International Organization 

for Standardization, Geneva. 1995. 

MCW 1961. Air Sampling Results in Building 301, Contains data covering the period 1958–

1961. Mallinckrodt Chemical Works (MCW), Uranium Division, Health and Safety 

Department, Weldon Spring, Missouri. 1961. SRDB 14945. 

NIOSH 2010. SEC Petition Evaluation Report, Petition SEC-00143, Rev. 0. National Institute 

for Occupational Safety and Health, Office of Compensation Analysis and Support, Cincinnati, 

Ohio. April 16, 2010. 

NIOSH 2011. White Paper for Weldon Spring Plant – Evaluation of Blunders Associated with 

Daily Weighted Average (DWA) Reports at the Weldon Spring Plant. National Institute for 

Occupational Safety and Health, Office of Compensation Analysis and Support, Cincinnati, 

Ohio. September 7, 2011.

SC&A 2010. Preliminary Issues from SC&A’s Review of NIOSH’s Evaluation Report for the 

Weldon Spring Site, Weldon Spring, Missouri, Special Exposure Cohort Petition SEC-00143. 

SCA-TR-TASK5-0015. SC&A, Inc., Vienna, Virginia, and Saliant, Inc., Jefferson, Maryland. 

October 2010.